1. Field
The present invention relates to a communication technique, and it particularly relates to a terminal apparatus, a communication system, and a communication method for transmitting the measured positional information.
2. Description of the Related Art
Since a mobile communication terminal such as a portable telephone is generally driven by a battery, it is desired that an access time to a mobile communication network be prolonged by suppressing the electric power consumed by the mobile communication terminal. For this reason, a plurality of mobile communication terminals mutually relay data between them using a short-range communication scheme, where a lower power is consumed than that consumed when access is made to the mobile communication network, and a mobile communication terminal having the largest remaining amount of battery accesses the mobile communication network, instead of the other mobile communication terminals.
Where a mobile communication terminal is equipped with a global positioning system (GPS) receiver, the positional information may sometimes be measured by the mobile communication terminal itself. The mobile communication terminal transmits the thus measured positional information via the mobile communication network. A position management system, which manages the positions of mobile communication terminals, collects a plurality of pieces of positional information measured by the plurality of mobile communication terminals via the mobile communication network and thereby manages the positions of the respective mobile communication terminals.
Since each mobile communication terminal transmits the positional information on a timely basis, the traffic amount in the mobile communication network increases. Measurement of positions by the GPS receivers also consumes the batteries of the mobile communication terminals. As a result, the access time to the mobile communication network is reduced.